Miley Cyrus celebrated her 19th birthday in style on Tuesday November 24th 2011, hitting the dance floor until 3am, the celebrations all being down to her pal Kelly Osbourne who organised the party for the 'Hannah Montana' star at plush Hollywood hotel, the Roosevelt and its Beacher's Madhouse room. A source told Us Weekly "Her mom Tish went, and so did her boyfriend Liam [Hemsworth]," going on to add "the group was up until 3 a.m. just dancing up a storm and having fun." Evidently Cyrus was hugely appreciative of the efforts Osbourne went to, taking to Twitter to tweet "Can't thank MissKellyO for the best partyyyy ever! =]]]] i loveeeee you! Let's just say there was a unicorn in the lobby! (sic)" The last part of that tweet would certainly suggest that the daughter of Ozzy managed to follow through with her intentions that the event was "going to be the sickout thing [Miley has] ever seen in her life." Osbourne had also said, "That was my mission for her, to make her birthday...the best day ever." The UK's Daily Mail also reported that there were dwarves in attendance, adding to the general feel of decadence.The pair became firm friends when on set together for forthcoming comedy film 'Undercover'.